targets (version 0.4.1)

tar_seed: Get the random number generator seed of the target currently running.

Description

Get the random number generator seed of the target currently running.

Usage

tar_seed(default = 1L)

Arguments

default

Integer, value to return if tar_seed() is called on its own outside a targets pipeline. Having a default lets users run things without tar_make(), which helps peel back layers of code and troubleshoot bugs.

Value

Integer of length 1. If invoked inside a targets pipeline, the return value is the seed of the target currently running, which is a deterministic function of the target name. Otherwise, the return value is default.

Details

A target's random number generator seed is a deterministic function of its name. In this way, each target runs with a reproducible seed so someone else running the same pipeline should get the same results, and no two targets in the same pipeline share the same seed. (Even dynamic branches have different names and thus different seeds.) You can retrieve the seed of a completed target with tar_meta(your_target, seed) and run set.seed() on the result to locally recreate the target's initial RNG state.

See Also

Other utilities: tar_cancel(), tar_envir(), tar_group(), tar_name(), tar_path(), tar_timestamp_raw(), tar_timestamp()

Examples

# NOT RUN {
tar_seed()
tar_seed(default = 123L)
if (identical(Sys.getenv("TAR_LONG_EXAMPLES"), "true")) {
tar_dir({ # tar_dir() runs code from a temporary directory.
tar_script(tar_target(returns_seed, tar_seed()), ask = FALSE)
tar_make()
tar_read(returns_seed)
})
}
# }